U.S. patent number 8,366,408 [Application Number 12/113,488] was granted by the patent office on 2013-02-05 for externally assisted valve for a positive displacement pump.
This patent grant is currently assigned to Schlumberger Technology Corporation. The grantee listed for this patent is Philippe Gambier, Rajesh Luharuka, Jean-Louis Pessin, Toshimichi Wago. Invention is credited to Philippe Gambier, Rajesh Luharuka, Jean-Louis Pessin, Toshimichi Wago.
United States Patent |
8,366,408 |
Wago , et al. |
February 5, 2013 |
Externally assisted valve for a positive displacement pump
Abstract
A positive displacement pump having a valve with an actuation
guide for assisting its actuation. The valve may be configured for
controlling fluid communication relative to a chamber of the pump
with the valve actuation guide positioned external to the chamber
and configured to assist in the controlling. The valve actuation
guide itself may include an arm extending into a valve actuation
assembly below the valve. In such embodiments, the arm may be
reciprocated by crankshaft, hydraulic, or other means.
Alternatively, the valve actuation assembly may include
electromagnetic means for assisting in actuation of the valve.
Inventors: |
Wago; Toshimichi (Houston,
TX), Gambier; Philippe (Houston, TX), Pessin;
Jean-Louis (Houston, TX), Luharuka; Rajesh (Stafford,
TX) |
Applicant: |
Name |
City |
State |
Country |
Type |
Wago; Toshimichi
Gambier; Philippe
Pessin; Jean-Louis
Luharuka; Rajesh |
Houston
Houston
Houston
Stafford |
TX
TX
TX
TX |
US
US
US
US |
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|
Assignee: |
Schlumberger Technology
Corporation (Sugar Land, TX)
|
Family
ID: |
39969703 |
Appl.
No.: |
12/113,488 |
Filed: |
May 1, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20080279705 A1 |
Nov 13, 2008 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60917366 |
May 11, 2007 |
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60985874 |
Nov 6, 2007 |
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Current U.S.
Class: |
417/298; 417/295;
251/65; 417/311 |
Current CPC
Class: |
F04B
53/1025 (20130101); F04B 53/1032 (20130101); F04B
49/243 (20130101); F04B 53/1097 (20130101); F04B
53/1022 (20130101); Y10T 137/7868 (20150401) |
Current International
Class: |
F04B
49/03 (20060101) |
Field of
Search: |
;417/109,295,298,454,510,567,311,446,503,505,506,507,508,559,561,568
;251/65 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1296061 |
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Mar 2003 |
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EP |
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1533516 |
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May 2005 |
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EP |
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Other References
Solenoid,
http://en.wikipedia.org/w/index.php?title=Solenoid&oldid=4437900-
91 (last visited Aug. 11, 2011). cited by examiner .
Office Action of Chinese Patent Application Serial No.
200880024290.6 dated Apr. 6, 2012. cited by applicant.
|
Primary Examiner: Freay; Charles
Assistant Examiner: Hamo; Patrick
Attorney, Agent or Firm: Stout; Myron Wright; Daryl Nava;
Robin
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION(S)
This Patent Document claims priority under 35 U.S.C. .sctn.119(e)
to U.S. Provisional Application Ser. No. 60/917,366, entitled Valve
for a Positive Displacement Pump filed on May 11, 2007, and
Provisional Application Ser. No. 60/985,874, entitled Valve for a
Positive Displacement Pump filed on Nov. 6, 2007, both of which are
incorporated herein by reference in their entirety.
Claims
We claim:
1. A positive displacement pump comprising: a housing for a
pressurizable chamber; a plunger configured to reciprocate inside
the pressurizable chamber; a valve of said housing for controlling
fluid communication with the pressurizable chamber; a valve
actuation guide external to the pressurizable chamber connected to
said valve by a coupling to assist opening or closing the valve to
control fluid communication with the pressurizable chamber; and, a
timing mechanism for controlling a timing of when the valve
actuation guide assists opening or closing the valve relative to a
position of the plunger inside the pressurizable chamber, and
wherein the timing mechanism is selected from the group consisting
of (i) a timing belt, and (ii) a sensor to monitor said position of
said plunger and a processor to analyze data from said sensor.
2. The positive displacement pump of claim 1 wherein the coupling
is of an electromagnetic nature.
3. The positive displacement pump of claim 2 wherein said valve
actuation guide is an electromagnetic power source coupled to at
least one electromagnetic inductor and said valve is of a
magneto-responsive material.
4. The positive displacement pump of claim 3 wherein the at least
one electromagnetic inductor is of reversible polarity.
5. The positive displacement pump of claim 3 wherein the at least
one electromagnetic inductor is accommodated at a valve seat for
contacting said valve.
6. The positive displacement pump of claim 1 further comprising a
mechanical arm disposed between said valve and said valve actuation
guide for the coupling.
7. The positive displacement pump of claim 6 wherein said
mechanical arm is of a contractible configuration.
8. The positive displacement pump of claim 6 wherein said valve
actuation guide is configured to drive said mechanical arm and
assist the valve to control fluid communication with the
pressurizable chamber by one of a cam mechanism, a crank mechanism,
a hydraulic mechanism, an electromagnetic mechanism, a servo motor,
and a stepper motor.
9. The positive displacement pump of claim 8 wherein said valve
actuation guide is configured to drive said mechanical arm by the
hydraulic mechanism, said mechanical arm further comprises a plate,
the hydraulic mechanism having a hydraulic mechanism housing
disposed about said plate to form a pressurizable compartment on at
least one side of the plate, said mechanical arm configured to
reciprocate in accordance with a pressure of the pressurizable
compartment when the mechanical arm is driven by the valve
actuation guide.
10. The positive displacement pump of claim 8 wherein said valve
actuation guide is configured to drive said mechanical arm by the
electromagnetic mechanism, said valve actuation guide is an
electromagnetic power source and the electromagnetic mechanism
includes at least one electromagnetic inductor.
11. The positive displacement pump of claim 10 wherein said
mechanical arm is of a magneto-responsive material.
12. The positive displacement pump of claim 10 wherein the at least
one electromagnetic inductor is of reversible polarity.
13. The positive displacement pump of claim 1 further comprising: a
power supply; the plunger coupled to said power supply and in
communication with the pressurizable chamber to direct a
pressurization of the pressurizable chamber; and where the timing
mechanism is a timing belt, the timing mechanism disposed between
said power supply and said valve actuation guide.
14. The positive displacement pump of claim 1 wherein control of
the timing for when the valve actuation guide assists opening or
closing the valve to control fluid communication with the
pressurizable chamber is tunable in real-time.
15. The positive displacement pump of claim 1 wherein said valve is
a first valve and said valve actuation guide is a first valve
actuation guide for connecting to said first valve, the positive
displacement pump further comprising: a second valve of said
housing for controlling fluid communication with the pressurizable
chamber; and a second valve actuation guide coupled to said second
valve to assist opening or closing the second valve to control
fluid communication with the pressurizable chamber.
16. The positive displacement pump of claim 1 wherein the valve is
configured to move in a direction that is substantially
perpendicular to a reciprocating movement of the plunger.
17. A positive displacement pump assembly for positioning at an
oilfield to deliver a fluid to a well thereat during an operation,
the positive displacement pump assembly comprising: a housing for a
pressurizable chamber; a plunger configured to reciprocate inside
the pressurizable chamber; a supply of the fluid adjacent the
pressurizable chamber; a valve of said housing for controlling
access by the fluid to the pressurizable chamber; a valve actuation
guide external to the pressurizable chamber connected to the valve
by a coupling to assist opening or closing the valve to control
fluid communication with the pressurizable chamber; and, a timing
mechanism for controlling a timing of when the valve actuation
guide assists opening or closing the valve relative to a position
of the plunger inside the pressurizable chamber, and wherein the
timing mechanism is selected from the group consisting of (i) a
timing belt, and (ii) a sensor to monitor said position of said
plunger and a processor to analyze data from said sensor.
18. The positive displacement pump assembly of claim 17 wherein the
coupling is one of a mechanical coupling and an electromagnetic
coupling.
19. The positive displacement pump assembly of claim 17 wherein the
operation is one of fracturing and cementing.
20. A valve actuation guide assembly for positioning adjacent a
housing for a pressurizable chamber of a positive displacement
pump, the valve actuation guide assembly comprising an actuation
guide connected to a valve of the housing by a coupling to control
fluid communication with the pressurizable chamber, wherein said
actuation guide assists opening or closing the valve to control
fluid communication with the pressurizable chamber, and a timing
mechanism for controlling a timing of when the valve actuation
guide assists opening or closing the valve relative to a position
of the plunger inside the pressurizable chamber, and wherein the
timing mechanism is selected from the group consisting of (i) a
timing belt, and (ii) a sensor to monitor said position of said
plunger and a processor to analyze data from said sensor.
21. The valve actuation guide assembly of claim 20 wherein the
coupling is one of electromagnetic and mechanical.
22. The valve actuation guide assembly of claim 20 wherein the
valve is configured to move in a direction that is substantially
perpendicular to a reciprocating movement of the plunger.
Description
FIELD
Embodiments described relate to valve assemblies for positive
displacement pumps used in high pressure applications. In
particular, embodiments of positive displacement pumps employing
mechanisms and supports for extending the life of pump valves,
minimizing pump damage during operation, and improving volumetric
efficiency are described.
BACKGROUND
Positive displacement pumps are often employed at oilfields for
large high pressure applications involved in hydrocarbon recovery
efforts. A positive displacement pump may include a plunger driven
by a crankshaft toward and away from a chamber in order to
dramatically effect a high or low pressure on the chamber. This
makes it a good choice for high pressure applications. Indeed,
where fluid pressure exceeding a few thousand pounds per square
inch (PSI) is to be generated, a positive displacement pump is
generally employed.
Positive displacement pumps may be configured of fairly large sizes
and employed in a variety of large scale oilfield operations such
as drilling, cementing, coil tubing, water jet cutting, or
hydraulic fracturing of underground rock. Hydraulic fracturing of
underground rock, for example, often takes place at pressures of
10,000 to 15,000 PSI or more to direct a solids containing fluid
through a well to release oil and gas from rock pores for
extraction. Such pressures and large scale applications are readily
satisfied by positive displacement pumps.
As noted, a positive displacement pump includes a plunger driven
toward and away from a pressurizable chamber in order to achieve
pumping of a solids containing fluid. More particularly, as the
plunger is driven away from the chamber, pressure therein reduces
allowing a discharge valve of the chamber to close. The chamber is
thus sealed off from the external environment while the plunger
remains in communication with the chamber. As such, the plunger
continues its retreat away from the chamber generating a lowered
pressure with respect to suction therein. Eventually, this lowered
pressure will reach a level sufficient to open a suction valve of
the pump in order to allow an influx of fluid into the chamber.
Subsequently, the plunger may be driven toward the chamber to once
again effect a high pressure therein. Thus, the suction valve may
be closed, the discharge valve re-opened, and fluid expelled from
the chamber as indicated above.
The actuation of the suction and discharge valves is achieved
primarily through reliance on pressure conditions generated within
the chamber. That is, the amount of pressure required to open or
close each valve is a function of the physical characteristics of
the valve along with a spring employed to hold the valve in a
naturally closed position relative to the chamber. Unfortunately,
this results in a lack of direct control over valve actuation and
leaves an inherent inefficiency in operation of the valves. For
example, opening of a valve requires generation of enough of a
pressure change so as to overcome the weight of the valve and
nature of its spring. This is of particular note regarding the
suction valve where, rather than opening immediately upon closure
of the discharge valve, a lowered pressure sufficient to overcome
the weight and nature of the suction valve and its spring must
first be generated within the chamber (i.e. net positive suction
head (NPSH)). This time delay in opening of the suction valve is an
inherent inefficiency in operation of the pump. Indeed, for a
standard positive displacement pump employed at an oilfield, a
pressure of between about 10 PSI and about 30 PSI may be required
within the chamber before the suction valve is opened.
Reliance solely upon internal chamber pressure to actuate valves
results in an inherent inefficiency and a lack of direct control as
indicated above. Of potentially greater concern however, is the
fact that this manner of valve actuation often leaves the pump
itself susceptible to significant damage as a result of cavitation
and `water hammering`. That is, as the plunger moves away from the
chamber decreasing pressure therein, the inherent delay in opening
of the suction valve may lead to the cavitation and subsequent
water hammering as described below.
During the delay in opening of the suction valve, and in
conjunction with the generation of lowered pressure in the chamber,
the fluid may undergo a degree of cavitation. That is, pockets of
vapor may form within the fluid and it may begin to vaporize in the
face of the lowered pressure. Formation of vapor in this manner may
be followed by rapid compression of the vapor back into liquid as
the plunger once again advances toward the chamber. This rapid
compression of the liquid is accompanied by a significant amount of
heat and may also result in transmitting a degree of shock through
the pump, referred to as water hammering. All in all, a significant
amount of pump damage may naturally occur based on the pressure
actuated design of a conventional positive displacement pump.
In order to address pump damage resulting from cavitation and water
hammering, techniques are often employed in which acoustic data
generated by the pump is analyzed during its operation. However,
reliance on the detection of acoustic data in order to address pump
damage fails to substantially avoid the development of pump damage
from cavitation and water hammering in the first place.
Furthermore, it is not uncommon for the damaged pump to be employed
in conjunction with an array of additional pumps at an oilfield.
Thus, the damage may see its effects at neighboring pumps, for
example, by placing added strain on these pumps or by translation
of the damaging water hammering effects to these pumps. Indeed,
cascading pump failure, from pump to pump to pump, is not an
uncommon event where a significant amount of cavitation and/or
water hammering is found.
SUMMARY
A positive displacement pump is provided with a housing for a
pressurizable chamber. The chamber may be defined in part by a
valve thereof which may be employed for controlling fluid access to
the chamber. The positive displacement pump may also include a
valve actuation guide that is positioned at least partially
external to the chamber and coupled to the valve so as to assist
the controlling of the fluid access to the chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of an embodiment of a positive displacement
pump employing a valve actuation guide assembly.
FIG. 2 is a cross-sectional view of the pump of FIG. 1 revealing an
embodiment of a valve actuation guide of the assembly.
FIG. 3 is a cross-sectional view of the pump of FIG. 1 revealing an
alternate embodiment of a valve actuation guide of the
assembly.
FIG. 4 is a cross-sectional view of the pump of FIG. 1 revealing
another alternate embodiment of a valve actuation guide of the
assembly.
FIG. 5 is a partially sectional overview of an oilfield employing
the pump of FIG. 1 as part of a multi-pump operation.
DETAILED DESCRIPTION
Embodiments are described with reference to certain high pressure
positive displacement pump assemblies for fracturing operations.
However, other positive displacement pumps may be employed for a
variety of other operations including cementing. Regardless,
embodiments described herein employ positive displacement pumps
with valves that are equipped with external actuation assistance.
As such, valve actuation is not left solely to the buildup of
cavitation-inducing conditions within a chamber of the pump which
would have the potential to create significant pump damage through
water hammering.
Referring now to FIG. 1, an embodiment of a positive displacement
pump 101 is shown which may employ a valve actuation guide assembly
100. The pump 101 may include a power supply depicted as a
crankshaft housing 150 coupled to a plunger housing 180 which is in
turn coupled to a chamber housing 175. In the embodiment shown, the
pump components may be accommodated at a conventional skid 130 to
enhance mobility, for example, for placement at an oilfield 501
(see FIG. 5). However, in other embodiments a pump truck or
alternatively less mobile pump configurations may be employed.
Additionally, the pump 101 may be of a conventional triplex
configuration as depicted. However, other positive displacement
pump configurations may also be employed.
Continuing with reference to FIGS. 1 and 2, the chamber housing 175
of the pump 101 may be configured with valves (250, 255) to draw
in, pressurize, and dispense an operation fluid. However, as
indicated, the valve actuation guide assembly 100 may also be
provided which is coupled to the chamber housing 175. The guide
assembly 100 may be configured to assist valves (e.g. 250) in
controlling or regulating fluid ingress and egress relative to the
chamber housing 175. As detailed herein-below, this valve
assistance provided by the guide assembly 100 may minimize pump
damage during operation and enhance overall efficiency of the pump
101.
With particular reference to FIG. 2, a valve actuation guide 200 of
the guide assembly 100 may be configured to assist in actuation of
a valve 255 of the chamber housing 175. In the embodiment shown,
the valve actuation guide 200 is mechanically coupled to the
suction valve 255 of the chamber housing 175. However, in other
embodiments, a valve actuation guide may similarly be coupled to
the discharge valve 250 of the housing 175 or other valves not
depicted. Additionally, as depicted in FIG. 2, the valve actuation
guide 200 may be of a crank-driven configuration as described
further below. However, in other embodiments, hydraulic,
electromagnetic, or other valve actuation assistance may be
employed.
Continuing with reference to FIGS. 1 and 2, the pump 101 is
provided with a plunger 290 reciprocating within a plunger housing
180 toward and away from a pressurizable chamber 235. In this
manner, the plunger 290 effects high and low pressures on the
chamber 235. For example, as the plunger 290 retreats away from the
chamber 235, the pressure therein will decrease. As the pressure
within the chamber 235 decreases, the discharge valve 250 may close
returning the chamber 235 to a sealed state. As the plunger 290
continues to move away from the chamber 235 the pressure therein
will continue to drop, and eventually a lowered pressure may begin
to arise within the chamber 235.
In spite of the potential development of lowered pressure within
the chamber 235 as indicated above, significant cavitation may be
avoided. That is, valve actuation assistance may be provided to the
suction valve 255 to effect its opening as depicted in FIG. 2. As
shown, the valve actuation guide 200 may be employed to ensure that
the suction valve 255 is raised in order to allow a communication
path 201 between a supply 245 of operation fluid and the chamber
235. As such, the uptake of operation fluid may be achieved without
sole reliance on lowered pressure overcoming a suction spring 275.
Thus, significant vaporization of operation fluid within the
chamber 235 may be avoided.
Avoidance of significant vaporization of operation fluid in this
manner may substantially minimize the amount of pump damage that
may otherwise result as the plunger 290 re-pressurizes and
condenses the operation fluid. That is, water-hammering damage due
to the rapid condensing of vaporized operation fluid may be largely
avoided. As such, in the embodiment shown, the plunger 290 may be
thrust toward the chamber 235, increasing the pressure therein. The
pressure increase will ultimately be enough to effect opening of
the discharge valve 250 overcoming the force supplied by the
discharge spring 270.
In an embodiment where the pump 101 is to be employed in a
fracturing operation, pressures may be achieved in the manner
described above that exceed 2,000 PSI, and more preferably, that
exceed 10,000 PSI or more. Furthermore, such a positive
displacement pump 101 is particularly well suited for high pressure
applications of abrasive containing operation fluids. In fact,
embodiments described herein may be applied to cementing, coil
tubing, water jet cutting, and hydraulic fracturing operations as
indicated, to name a few.
As indicated, the valve actuation guide 200 is configured to assist
in actuation of the suction valve 255 as detailed above. However,
the valve actuation guide 200 may take a variety of configurations
in order to provide such assistance. For example, in the particular
embodiment of FIG. 2, the valve actuation guide 200 is of a
crank-driven configuration. As such, an arm 205 is provided
extending from the suction valve 255 away from the chamber 235 and
to the guide assembly 100. In the embodiment shown, the arm 205 is
coupled to a rotable crankshaft 207 through a pin 209. The
crankshaft 207 is rotable about a central axis 210. Thus, as the
crankshaft 207 rotates, it serves to raise and lower the arm 205.
In this manner, actuation of the suction valve 255 is achieved
based on the rotation of the crankshaft 207 as opposed to sole
reliance on lowered pressure within the chamber 235 as indicated
above.
As indicated above, the proper timing for actuation of the suction
valve 255 is dependent upon the position of the plunger 290,
relative to the chamber 235. Thus, as described below, a mechanism
for synchronizing the timing of the valve actuation guide 200 and
its crankshaft 207 with the plunger 290 may be provided.
Additionally, in the embodiment shown, the arm 205 is reciprocated
in a rectilinear manner so as to maintain isolation between the
guide assembly 100 and the operation fluid supply 245. This may be
achieved through the employment of a crankshaft 207 of a
conventional rectilinear effectuating crank design. Alternatively,
other methods of sealing between the guide assembly 100 and the
operation fluid supply 245 may be employed or a tolerable degree of
communication there-between may be allowed.
As indicated above, and with added reference to FIG. 1, a mechanism
for synchronizing the timing of the valve actuation guide 200 and
the plunger 290 may be provided. As depicted in FIG. 1, the
positive displacement pump 101 includes a timing mechanism in the
form of a timing belt 125 running between the crankshaft housing
150 and the valve actuation guide assembly 100. More particularly,
the timing belt 125 is positioned between a crank gear 155 at the
crankshaft housing 150 and an assembly gear 110 at the guide
assembly 100. The crank gear 155 may be coupled to the crankshaft
of the crankshaft housing 150 which drives the plunger 290. By
contrast, the assembly gear 110 may be coupled to the crankshaft
207 of the guide assembly 100. Thus, rotation of the crankshaft of
the crankshaft housing 150 drives the plunger 290 as indicated,
while also driving the valve actuation guide 200. Therefore, with
appropriately sized intervening gears 155, 110 and other equipment
parts, precise synchronized timing of the valve actuation guide 200
in line with the reciprocating plunger 290 may be achieved.
Additionally, in other embodiments, the valve actuation guide 200
may be mechanically linked to the power output of the pump 101
through alternate means. Regardless, the volumetric efficiency of
the pump operation may be enhanced in addition to the substantial
elimination of cavitation and pump damage as described above with
such a degree of synchronization employed.
Continuing with reference to FIG. 2, the arm 205 of the valve
actuation guide 200 is depicted as a monolithic linkage between the
suction valve 255 and the rotable crankshaft 207. However, in one
embodiment the arm 205 may be contractible, similar to a
conventional shock absorber. In this manner, the suction valve 255
may continue to be pressure actuated based on pressure within the
chamber 235 in the event that the rotable crankshaft 207 ceases
rotation or otherwise fails to properly operate. For example, with
a contractible arm 205, the suction valve 255 may avoid being stuck
in an open position as depicted in FIG. 2 should the valve
actuation guide 200 malfunction or cease to operate.
The valve actuation guide 200 described above includes a crankshaft
207 for actuating the suction valve 255 in both an open direction,
as depicted in FIG. 2, as well as in a closed direction (e.g. when
the plunger 290 returns toward the chamber 235). However, this type
of external valve assistance may take place to greater or lesser
degrees. For example, in one embodiment, the valve actuation guide
200 may include a rotable cam in place of the rotable crankshaft
207. Thus, the arm 205 may be forced upward by the cam during its
rotation in order to open the valve 255. However, returning closed
of the valve 255 may be left to pressure buildup within the chamber
235. Thus, significant cavitation may be avoided as the suction
valve 255 is opened without sole reliance on lowered pressure
within the chamber 235. As such, employing a return of higher
pressure within the chamber to close the suction valve 255 is less
likely to result in any significant water hammering.
Similarly, the embodiments depicted reveal the guide assembly 100
and actuation guide 200 adjacent only to the suction valve 255.
That is, actuation of the discharge valve 250 is left to pressure
conditions within the chamber 235. This may allow for ease of
design similar to cam actuation noted above and may be a practical
option in light of the fact that significant cavitation is unlikely
correlated to any discharge valve 250 position. However, in one
embodiment external assistance is provided to the discharge valve
250 in addition to the suction valve 255. That is, an additional
actuation guide similar to the embodiments described above may be
positioned adjacent the discharge valve 250 and coupled thereto in
order to further enhance pump efficiency. This may take place by
reducing the amount of time that might otherwise be required to
open or close the discharge valve 250 based solely on the pressure
within the chamber 235.
Referring now to FIG. 3, an alternate embodiment of an actuation
guide 300 is depicted within the guide assembly 100. Namely, a
hydraulic actuation guide 300 may be employed in order to provide
external assistance to a valve such as the depicted suction valve
255. In the embodiment shown, an arm 305 once again extends from
the suction valve 255 to the external guide assembly 100 where it
terminates at a plate 307 within a hydraulic chamber 309. As
described below, hydraulic fluid within the chamber 309 may act
upon the plate 307 in order to effect reciprocation of the arm 305.
In this manner, the suction valve 255 may be assisted in either
opening to the position shown in FIG. 3 or in closing.
Continuing with reference to FIG. 3, the actuation guide 300
includes the noted hydraulic chamber 309 which may be divided into
a pump-side interior compartment 330 and an exterior compartment
340 at either side of the plate 307. Thus, an increase in pressure
at the interior compartment may be employed to drive the arm 305
away from the adjacent pump equipment. In the case of the suction
valve 255 coupled to the arm 305, this pressure increase results in
a closing of the valve 255 and the communication path 201 between
the fluid supply 245 and the pump chamber 235. Alternatively, a
pressure increase within the exterior compartment 340 may act upon
the opposite side of the plate 307 to drive the suction valve 255
into the open position depicted in FIG. 3. Of note is the fact that
in an embodiment where a hydraulic actuation guide 300 is also
coupled to the discharge valve 250, an increase in pressure at its
pump side interior compartment would act to open the valve 250.
Alternatively, an increase in pressure at the opposite exterior
compartment would act to close the valve 250. This manner of
actuation would be due to the unique orientation of the discharge
valve 250 relative to the pump chamber 235.
Returning to the embodiment depicted in FIG. 3, the interior
compartment 330 is served by an interior hydraulic line 310 whereas
the exterior compartment is served by an exterior hydraulic line
320. Thus, in one embodiment a double acting hydraulic control
mechanism may be disposed between the lines 310, 320 to drive
hydraulic fluid between the lines 310, 320 in order to regulate
pressure within the compartments 330, 340 as described.
Alternatively, synchronized independently actuated double acting
pneumatic actuators may be coupled to each line 310, 320 in order
to direct pressures within the compartments 330, 340 and achieve
reciprocation of the arm 305.
Similar to the crank-driven configuration of FIG. 2, the hydraulic
valve actuation guide 300 of FIG. 3 provides valve actuation
assistance to the suction valve in a manner substantially reducing
cavitation or boiling of operation fluid within the chamber 235
during retreat of the plunger 290. Additionally, where the
actuation guide 300 assists in both opening and closing of the
suction valve 255 in a synchronized manner, volumetric efficiency
of the pump is also enhanced. Furthermore, additional volumetric
efficiency may be achieved in an embodiment where a hydraulic
actuation guide 300 is also coupled to the discharge valve 250 as
described above.
As in the case of the crank-driven configuration of FIG. 2, the arm
305 may also be of a shock-absorber configuration to ensure
continued valve operation in the event of breakdown of the
actuation guide 300. Additionally, the hydraulic actuation guide
300 may be employed for assistance in valve actuation in a single
direction (e.g. opening of the suction valve 255 similar to the cam
actuated embodiment described above).
Continuing now with reference to FIG. 4, another alternate
embodiment of an actuation guide 450 is depicted within the guide
assembly 100. In this case, the actuation guide is an
electromagnetic power source that is wired through leads 421, 441
to an electromagnetic inductor 420. Thus, in the embodiment shown,
the suction valve 255 may be of a conventional magnetic or other
magneto-responsive material such that valve actuation may be
directionally assisted based on the polarity of the inductors 420.
That is, the inductor 420 may be of reversible polarity such that
the valve 255 will either be assisted in opening or closing
depending on the magnitude and polarity of the current through the
inductor 420.
In the embodiment of FIG. 4, the actuation guide 450 remains
entirely free of physical coupling to the suction valve 255 by way
of imparting electromagnetic forces through the inductor 420
imbedded within the seat below the suction valve 255 and adjacent
the fluid supply 245. However, in another embodiment, an arm
similar to that of FIGS. 2 and 3 may be coupled to the valve 255
and extend toward the guide assembly 100. In such an embodiment, an
inductive mechanism may be retained isolated from the fluid supply
245 where desired. Thus, the arm, as opposed to the valve 255
itself, may be made up of magnetic or magneto-responsive material
and acted upon by the inductive mechanism to assist valve actuation
similar to the mechanical and hydraulic embodiments depicted in
FIGS. 2 and 3.
As with prior embodiments detailed above, the electromagnetic
driven configuration of FIG. 4 provides valve actuation assistance
to the suction valve in a manner substantially reducing cavitation.
Additionally, where the actuation guide 450 induces a synchronized
reverse of polarity to assist in both opening and closing of the
suction valve 255, volumetric efficiency of the pump is also
enhanced. Furthermore, additional volumetric efficiency may be
achieved in an embodiment where an electromagnetic actuation guide
450 is also coupled to the discharge valve.
With particular reference to FIGS. 3 and 4, hydraulic and
electromagnetic valve actuation assistance may be particularly well
suited for non-mechanical synchronization with the power output of
the pump. That is, rather than physically employing a timing belt
125 to link power output and the guide assembly 100, the position
of the plunger 290 or other pump parts may be monitored via
conventional sensors and techniques. This information may then be
fed to a processor where it may be analyzed and employed in
actuating the hydraulic 300 or electromagnetic 450 actuation guides
employed. Indeed, with such techniques available, actuation
assistance may be tuned in real-time to ensure adequate avoidance
of cavitation and maximization of volumetric pump efficiency.
Continuing with reference to the embodiments of FIGS. 3 and 4,
non-intrusive actuation assistance in the form of hydraulic 300 or
electromagnetic 450 actuation guides provides additional
advantages. For example, there is a reduction in the total number
of mechanical moving parts which must be maintained. Indeed, in the
case of electromagnetic actuation, in particular, the option of
eliminating an arm coupled to the valve 255 alleviates concern over
the potential need to maintain a sealed off fluid supply 245.
Referring now to FIG. 5, a partially sectional view of an oilfield
501 is depicted whereat pumps 101 such as that of FIG. 1 are
employed as part of a multi-pump operation. Each pump 101 is
equipped with a crankshaft housing 150 adjacent a chamber housing
175 and positioned atop a skid 130. However, in order to reduce
cavitation and pump damage, the pumps 101 are also each equipped
with an externally positioned guide assembly 100 to assist in valve
actuation within the chamber housing 175 as detailed in embodiments
above. Overall pump efficiency may also be enhanced for each of the
pumps 101 in this manner. Thus, inadequate operation of any given
pump 101 is unlikely to occur or place added strain on neighboring
pumps 101.
In the particular depiction of FIG. 5, the pumps are acting in
concert to deliver a fracturing fluid 510 through a well 525 for
downhole fracturing of a formation 515. In this manner, hydrocarbon
recovery from the formation 515 may be stimulated. Mixing equipment
590 may be employed to supply the fracturing fluid 510 through a
manifold 575 where pressurization by the pumps 101 may then be
employed to advance the fluid 510 through a well head 550 and into
the well 525 at pressures that may exceed about 20,000 PSI.
Nevertheless, due to cavitation avoidance as a result of the
employed guide assemblies 100, pump damage due to water hammering
may be kept at a minimum.
Embodiments described hereinabove address cavitation, pump damage
and even pump efficiency in a manner that does not rely solely upon
internal pump pressure for valve actuation. As a result, delay in
opening of the suction valve in particular may be avoided so as to
substantially eliminate cavitation and subsequent water hammering.
Indeed, as opposed to mere monitoring of pump conditions,
embodiments described herein may be employed to actively avoid pump
damage from water hammering.
The preceding description has been presented with reference to
presently preferred embodiments. Persons skilled in the art and
technology to which these embodiments pertain will appreciate that
alterations and changes in the described structures and methods of
operation may be practiced without meaningfully departing from the
principle, and scope of these embodiments. For example, valve
actuation assistance may be achieved through the use of servo
and/or stepped motors. The assistance as detailed herein may also
be employed to extend the life of valves by increasing the rate of
valve closure so as to ensure more effective crushing of abrasives
carried by operation fluid. Additionally, volumetric efficiencies
enhanced by valve actuation assistance as described herein may be
even further enhanced by ensuring that valve opening is maximized
during pumping. Furthermore, the foregoing description should not
be read as pertaining only to the precise structures described and
shown in the accompanying drawings, but rather should be read as
consistent with and as support for the following claims, which are
to have their fullest and fairest scope.
* * * * *
References